Field of the Invention
The present invention relates to a container having an open bottom, and a bottom cap for closing and hermetically sealing the open bottom. More particularly, the present invention is directed to such a container and bottom cap in which the bottom cap has a sealant material bonded thereto for forming the hermetic seal.
Containers having integral bottoms or bottom walls are well known. However, such containers can be problematic, especially elongated and/or narrow diameter containers whose remote portions are difficult to reach and effectively clean. In an effort to alleviate this problem, such containers, for example bottles and cups for feeding babies, have been formed as a container assembly having a body with an open bottom, and a removable bottom cap, to allow easy access to and separate and thorough cleaning of each component. These container assemblies require a hermetic seal between the open bottom of the container and the bottom cap. The hermetic seal has been obtained by employing a sealing structure, such as an annular ring seal, that is separate and removable from the other assembly components. However, employing a separate sealing structure renders the container assembly more complicated to assemble and, thus, use. If it is not removed and cleaned, there is the possibility that undesirable matter, e.g. liquid, food, and the like will accumulate or form between the separate sealing structure and its underlying surface.
It is desired to have a sealing system for a container assembly with a removable bottom cap that overcomes the aforementioned shortcomings.
It is an object of the present invention to provide a hermetic sealing system for a container assembly having a container with a removable bottom cap.
It is another object of the present invention to provide such a sealing system in which the sealant is bonded to the bottom cap of the container assembly.
It is yet another object of the present invention to provide such a container assembly in which the sealant in the bottom cap provides the hermetic seal between the bottom cap and the container.
It is a further object of the present invention to provide an alternative sealant that is secured to the container to provide a hermetic seal between the bottom cap and the container.
It is still another object of the present invention to provide such a container assembly in which the bottom cap has a sealant material bonded thereto for providing a hermetic seal between the bottom cap and the open bottom of the container and, simultaneously provides a grip surface through or slightly beyond the exterior surface of the bottom cap to contact a substrate, such as a table.
The present invention includes a bottom cap for closing and hermetically sealing the open bottom end of a container. The bottom cap includes a bottom wall having a peripheral portion, a side wall extending upwardly from the peripheral portion and means for securing the bottom cap to the open bottom end of the container. The peripheral portion includes a peripheral continuous, preferably annular, layer of sealant material bonded thereto that is adapted to hermetically seal the bottom end of the container when the bottom cap is secured thereto.
The present invention also includes a container assembly comprised of a container having an open bottom end with a downwardly directed sealing surface, means for securing a bottom cap to the open bottom end, a bottom cap, and a continuous, preferably annular, layer or strip of compressible sealant material bonded to the container assembly. The strip is adapted so that when the bottom cap is secured to the open bottom end, the strip is between the sealing surface and the bottom wall, and the sealing surface compresses the strip against the bottom wall thereby forming a hermetic seal between the container and the bottom cap. In the container assembly, the strip is preferably bonded to the interior surface of the bottom wall of the bottom cap.
Also preferably, the peripheral portion of the bottom cap has holes therethrough and the sealant material extends into and slightly through the holes. The sealant material that extends into the holes preferably extends below the bottom surface of the bottom wall of each hole, where it can be in the form of an individual bead below each hole. Each bead preferably has a peripheral edge that underlies and is bonded to the bottom surface of the bottom wall. Also preferably, the peripheral portion has an annular series of circumferentially spaced holes therethrough, and the sealant material of the strip extends through and below the holes, and is in the form of a continuous, preferably annular, layer that is fused to the bottom surface of the peripheral portion.
The present invention also includes a method of forming the bottom cap of the present invention. The method includes forming the bottom cap of a first material, and injecting a sealant material onto the peripheral portion of the bottom cap so that the sealant material forms an annular layer on the peripheral portion. The injection step is effected at a temperature and under conditions sufficient to fuse the layer of sealant material to the peripheral portion. The forming step preferably includes forming an annular series of circumferentially spaced holes through the peripheral portion of the bottom wall, and the injecting step preferably includes flowing the sealant material through and below the holes so that the sealant material below the holes forms either a series of beads or an underlying annular layer that is fused to the bottom surface of the bottom wall. Preferably, the underlying layer is formed so that it has outer edges that underlie the bottom wall adjacent the holes. In the method, the bottom cap is preferably polypropylene, and the sealant material is preferably a thermoplastic elastomer having a Shore A Hardness from about 40 to about 50.